Ultrasonic echoes from deliberately launched diagnostic sound waves into tissue are attenuated in proportion to the distance that the sound waves must travel to reach the reflector, plus the distance that the resulting echoes must travel back to reach the receiver. Since sound waves are attenuated as they pass through the human body, the deeper the penetration, the greater the attenuation.
Ultrasound machines which support simultaneous B, color and Doppler imaging restrict the color and Doppler velocity scales which the user can select. Such machines may also or alternatively change the color and Doppler velocity scales together when only one has been requested to be changed. The firing sequence used is predetermined and often probe dependent. The restrictions placed on the user do not allow the user to manipulate the machine in a manner most appropriate for imaging particular anatomy and patients.
In order to increase the frame rate, it is possible to interleave B mode vectors with pulsed echoes (PE), i.e., Doppler, vectors. It is also possible to interleave color firings. Interleaving PE Doppler vectors and B vectors means firing one or more B vectors within the pulse repetition interval (PRI) of the Doppler vectors while maintaining the pulse repetition interval of the Doppler vector. Interleaving PE Doppler vectors and color vectors means firing color vectors within the pulse repetition interval of the Doppler vectors while maintaining the pulse repetition interval of the Doppler and color vectors. Interleaving color vectors with other color vectors means firing one or more color vectors within the pulse repetition interval of another color vector while maintaining the pulse repetition interval of all of the color vectors.
Current ultrasound machines determine whether interleaving is possible, and perform the interleaving, based upon fixed protocols. Unfortunately, the fixed protocols do not always allow interleaving for a particular image when it is possible and, therefore, the maximum frame rate is not attained. Furthermore, the fixed protocols do not always generate the maximum amount of interleaving for a particular image, again, not attaining the maximum frame rate.
It would be desirable then to have a dynamic firing sequence for an ultrasound imaging machine which maximizes frame rate and maximizes interleaving.